1. Field of the Invention
The present invention relates to a tactile sensor, and more particularly to a tactile sensor and a method of manufacturing the same, which are capable of implementing a wide range of senses, including sensing contact pressure with an external object and heat caused by the contact pressure.
2. Description of the Related Art
At present, tactile functionalities to obtain information about environments, for example, contact pressure, surface roughness, temperature variation to thermal conductivity, etc., through contact is recognized as information acquisition media. Biomimic tactile sensors replacing human tactile sense are becoming increasingly important since they can be not only used for various medical treatments, diagnoses, and administrations, such as intravascular microscopic operation and cancer diagnosis, but also applied to tactile presentation technologies which are important for the future of virtual environment implementation technology.
As examples of the biomimic tactile sensors, force/torque sensors having 6 degrees of freedom used for wrists of industrial robots and sensors for detecting contact pressure and instantaneous slip for use in grippers of robots have been developed, however, these sensors have a problem of low sensitivity due to relatively large sensing units.
In addition, development possibility of the tactile sensors using MEMS (micro electro mechanical systems) manufacture technologies has been shown, however, these tactile sensors have a limitation in terms of acquisition of information about external environments since they are manufactured to acquire only information about contact pressure.
Accordingly, in order to develop practical biomimic tactile sensors, specifications of sensors for implementing a wide range of senses, including sensing contact pressure of skin with an external object and heat caused by the contact pressure are required.
In addition, in order to achieve smooth interaction between the biomimic tactile sensors and the surroundings, development of high speed signal processing systems for multi-channel array sensors according to sensor fusion is required.
On the other hand, as shown in FIG. 1, a force sensor P manufactured using the MEMS technology is configured as a rectangular film-type sensing unit encountering three loadings Fx, Fy and Fz. The sensing unit consists of a loading block 16 and a side block 17 for supporting the overall structure. A overload protection block 18, which is manufactured using a silicon micromachining technique, for preventing breakage of the sensing unit when overload is imposed on the sensing unit is bonded to the sensing unit.
FIG. 2 is a plan view illustrating a tactile sensor manufactured using the MEMS technology and FIG. 3 is a circuit diagram of FIG. 2. As shown in FIGS. 2 and 3, four fine force sensors P each consisting of the loading block 16 and the side block 17 as described above and four heat sensors T each consisting of a metal line for temperature measurement 13 and a heater 14 are formed on a wafer 1. This application relates to manufacture of a practical tactile sensor using the MEMS technology.